Abstract
Three different anesthetic delivery systems, facemask (FM), endotracheal tube (ETT), and laryngeal mask airway (LMA™ North America Inc., San Diego, CA, USA) were compared in Indian peafowl (Pavo cristatus). Fifteen birds were randomly divided into three groups of five for each delivery system and immobilized with isoflurane (AErrane®, Baxter Healthcare Corporation, Deerfield, IL, USA) delivered in 100% oxygen. Birds were induced via facemask and maintained for 20 minutes for initial set-up, then changed to the assigned delivery system for approximately 40 minutes, during which the following values were monitored and compared: heart rate, spontaneous respiratory rate, body temperature, saturation of peripheral oxygen (SpO2), and end-tidal carbon dioxide (ETCO2) (Table 1). Intermittent positive pressure ventilation was provided at 6–10 breaths/minutes. SpO2 values were obtained using the SurgiVet® pulse oximeter (BCI, Inc., Waukesha, WI, USA) and ETCO2 values were obtained using the TIDAL WAVE® Sp handheld capnograph/oximeter (Novametrix Medical Systems, Inc., Wallingford, CT, USA). Arterial samples were obtained for blood gas analysis performed by the i-STAT® Portable Clinical Analyzer (i-STAT Corporation, East Windsor, NJ, USA) (Table 2). Radiographs were performed at the end of the procedure with no birds demonstrating excessive air within the gastrointestinal system. Anesthetic depth and recovery were subjectively similar across groups. Tracheoscopy was performed in all birds 13–20 days after initial immobilizations to evaluate tracheal mucosa. There was no evidence of tracheal damage in the FM and LMA groups, but one bird in the ETT group developed a tracheal stricture requiring surgical resection and anastomosis.
Table 1. Comparative physiologic parameters for Indian peafowl (Pavo cristatus) during isoflurane anesthesia via three different anesthetic delivery systems (n=5 in each group).
Values are reported as mean ± standard deviation.a
|
|
HR
(beats/m)
|
RR
(breaths/m)
|
T (°C)
|
SpO2 (%)
|
ETCO2 (mm Hg)
|
|
FM
|
146 ± 30
|
6 ± 2
|
39.1 ± 0.7
|
96 ± 4
|
13 ± 5
|
|
ETT
|
214 ± 36
|
10 ± 4
|
38.9 ± 0.8
|
95 ± 5
|
41 ± 14
|
|
LMA
|
174 ± 38
|
5 ± 4
|
38.9 ± 0.6
|
98 ± 2
|
32 ± 9
|
aFM, facemask; ETT, endotracheal tube; LMA, laryngeal mask airway; HR, heart rate; RR, spontaneous respiratory rate; T, temperature (cloacal); SpO2, saturation of peripheral oxygen; ETCO2, end-tidal carbon dioxide.
Table 2. Comparative blood gas analysis for Indian peafowl (Pavo cristatus) during isoflurane anesthesia via three different anesthetic delivery systems (n=5 in each group).
Values are reported as mean ± standard deviation.a
|
|
Lac
(mmol/L)
|
TCO2
(mmol/L)
|
pH
|
PCO2
(mm Hg)
|
PO2
(mm Hg)
|
HCO3
(mmol/L)
|
BEecf
(mmol/L)
|
sO2 (%)
|
|
FM
|
0.68 ± 0.29
|
38 ± 3
|
7.376 ± 0.105
|
62.8 ± 17.7
|
342 ± 135
|
35.6 ± 2.7
|
11 ± 3
|
99 ± 1
|
|
ETT
|
1.10 ± 1.19
|
40 ± 2
|
7.287 ± 0.107
|
81.3 ± 20.3
|
224 ± 121
|
38.2 ± 2.1
|
12 ± 3
|
98 ± 2
|
|
LMA
|
0.41 ± 0.18
|
38 ± 4
|
7.332 ± 0.067
|
70.2 ± 16.5
|
316 ± 128
|
36.4 ± 4.0
|
10 ± 3
|
99 ± 1
|
aFM, facemask; ETT, endotracheal tube; LMA, laryngeal mask airway; Lac, lactate; TCO2, total carbon dioxide; p concentration; PCO2, partial pressure of carbon dioxide; PO2, partial pressure of oxygen; HCO3, bicarbonate; BEec extracellular fluid; sO2, oxygen saturation.
Acknowledgments
This study was approved by the Institutional Animal Care and Use Committee and financially supported by a grant from the Species Survival Fund of the Wildlife Conservation Society. The authors thank the veterinary technicians at the Bronx Zoo for their assistance with the anesthetic procedures, and the staffs of the Ornithology and Pathology Departments for their contributions.